The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 11, 2003
Filed:
Jul. 02, 2001
Alin Theodor Iacob, Sunnyvale, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A VFD driver circuit includes a DC power supply coupled to cascaded first power operational amplifier (POA ) and second power operational amplifier (POA ). The POA is a self-oscillating power operational amplifier having a feedback circuit associated therewith whereas the POA is configured in an essentially inverting unity gain mode. The POA has a first POA output node coupled to a first terminal of a VFD filament and a second POA output node coupled to a first POA input node. The POA has a POA output node coupled to a second terminal of the VFD filament. The shape of the output waveform delivered by the POA is dependent upon the feedback circuit and can be any shape deemed suitable. Such shapes include a square wave, a sinusoidal wave, a triangular wave, a trapezoidal wave, clipped sinusoidal wave, and so on.